1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Integrity Measurement Architecture
4 *
5 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
6 *
7 * Authors:
8 * Reiner Sailer <sailer@watson.ibm.com>
9 * Serge Hallyn <serue@us.ibm.com>
10 * Kylene Hall <kylene@us.ibm.com>
11 * Mimi Zohar <zohar@us.ibm.com>
12 *
13 * File: ima_main.c
14 * implements the IMA hooks: ima_bprm_check, ima_file_mmap,
15 * and ima_file_check.
16 */
17
18 #include <linux/module.h>
19 #include <linux/file.h>
20 #include <linux/binfmts.h>
21 #include <linux/kernel_read_file.h>
22 #include <linux/mount.h>
23 #include <linux/mman.h>
24 #include <linux/slab.h>
25 #include <linux/xattr.h>
26 #include <linux/ima.h>
27 #include <linux/fs.h>
28 #include <linux/iversion.h>
29 #include <linux/evm.h>
30 #include <linux/crash_dump.h>
31
32 #include "ima.h"
33
34 #ifdef CONFIG_IMA_APPRAISE
35 int ima_appraise = IMA_APPRAISE_ENFORCE;
36 #else
37 int ima_appraise;
38 #endif
39
40 int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1;
41 static int hash_setup_done;
42 static int ima_disabled __ro_after_init;
43
44 static struct notifier_block ima_lsm_policy_notifier = {
45 .notifier_call = ima_lsm_policy_change,
46 };
47
ima_setup(char * str)48 static int __init ima_setup(char *str)
49 {
50 if (!is_kdump_kernel()) {
51 pr_info("Warning: ima setup option only permitted in kdump");
52 return 1;
53 }
54
55 if (strncmp(str, "off", 3) == 0)
56 ima_disabled = 1;
57 else if (strncmp(str, "on", 2) == 0)
58 ima_disabled = 0;
59 else
60 pr_err("Invalid ima setup option: \"%s\" , please specify ima=on|off.", str);
61
62 return 1;
63 }
64 __setup("ima=", ima_setup);
65
hash_setup(char * str)66 static int __init hash_setup(char *str)
67 {
68 struct ima_template_desc *template_desc = ima_template_desc_current();
69 int i;
70
71 if (hash_setup_done)
72 return 1;
73
74 if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
75 if (strncmp(str, "sha1", 4) == 0) {
76 ima_hash_algo = HASH_ALGO_SHA1;
77 } else if (strncmp(str, "md5", 3) == 0) {
78 ima_hash_algo = HASH_ALGO_MD5;
79 } else {
80 pr_err("invalid hash algorithm \"%s\" for template \"%s\"",
81 str, IMA_TEMPLATE_IMA_NAME);
82 return 1;
83 }
84 goto out;
85 }
86
87 i = match_string(hash_algo_name, HASH_ALGO__LAST, str);
88 if (i < 0) {
89 pr_err("invalid hash algorithm \"%s\"", str);
90 return 1;
91 }
92
93 ima_hash_algo = i;
94 out:
95 hash_setup_done = 1;
96 return 1;
97 }
98 __setup("ima_hash=", hash_setup);
99
ima_get_current_hash_algo(void)100 enum hash_algo ima_get_current_hash_algo(void)
101 {
102 return ima_hash_algo;
103 }
104
105 /* Prevent mmap'ing a file execute that is already mmap'ed write */
mmap_violation_check(enum ima_hooks func,struct file * file,char ** pathbuf,const char ** pathname,char * filename)106 static int mmap_violation_check(enum ima_hooks func, struct file *file,
107 char **pathbuf, const char **pathname,
108 char *filename)
109 {
110 struct inode *inode;
111 int rc = 0;
112
113 if ((func == MMAP_CHECK || func == MMAP_CHECK_REQPROT) &&
114 mapping_writably_mapped(file->f_mapping)) {
115 rc = -ETXTBSY;
116 inode = file_inode(file);
117
118 if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */
119 *pathname = ima_d_path(&file->f_path, pathbuf,
120 filename);
121 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname,
122 "mmap_file", "mmapped_writers", rc, 0);
123 }
124 return rc;
125 }
126
127 /*
128 * ima_rdwr_violation_check
129 *
130 * Only invalidate the PCR for measured files:
131 * - Opening a file for write when already open for read,
132 * results in a time of measure, time of use (ToMToU) error.
133 * - Opening a file for read when already open for write,
134 * could result in a file measurement error.
135 *
136 */
ima_rdwr_violation_check(struct file * file,struct ima_iint_cache * iint,int must_measure,char ** pathbuf,const char ** pathname,char * filename)137 static void ima_rdwr_violation_check(struct file *file,
138 struct ima_iint_cache *iint,
139 int must_measure,
140 char **pathbuf,
141 const char **pathname,
142 char *filename)
143 {
144 struct inode *inode = file_inode(file);
145 fmode_t mode = file->f_mode;
146 bool send_tomtou = false, send_writers = false;
147
148 if (mode & FMODE_WRITE) {
149 if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
150 if (!iint)
151 iint = ima_iint_find(inode);
152
153 /* IMA_MEASURE is set from reader side */
154 if (iint && test_and_clear_bit(IMA_MAY_EMIT_TOMTOU,
155 &iint->atomic_flags))
156 send_tomtou = true;
157 }
158 } else {
159 if (must_measure)
160 set_bit(IMA_MAY_EMIT_TOMTOU, &iint->atomic_flags);
161
162 /* Limit number of open_writers violations */
163 if (inode_is_open_for_write(inode) && must_measure) {
164 if (!test_and_set_bit(IMA_EMITTED_OPENWRITERS,
165 &iint->atomic_flags))
166 send_writers = true;
167 }
168 }
169
170 if (!send_tomtou && !send_writers)
171 return;
172
173 *pathname = ima_d_path(&file->f_path, pathbuf, filename);
174
175 if (send_tomtou)
176 ima_add_violation(file, *pathname, iint,
177 "invalid_pcr", "ToMToU");
178 if (send_writers)
179 ima_add_violation(file, *pathname, iint,
180 "invalid_pcr", "open_writers");
181 }
182
ima_check_last_writer(struct ima_iint_cache * iint,struct inode * inode,struct file * file)183 static void ima_check_last_writer(struct ima_iint_cache *iint,
184 struct inode *inode, struct file *file)
185 {
186 fmode_t mode = file->f_mode;
187 bool update;
188
189 if (!(mode & FMODE_WRITE))
190 return;
191
192 mutex_lock(&iint->mutex);
193 if (atomic_read(&inode->i_writecount) == 1) {
194 struct kstat stat;
195
196 clear_bit(IMA_EMITTED_OPENWRITERS, &iint->atomic_flags);
197
198 update = test_and_clear_bit(IMA_UPDATE_XATTR,
199 &iint->atomic_flags);
200 if ((iint->flags & IMA_NEW_FILE) ||
201 vfs_getattr_nosec(&file->f_path, &stat,
202 STATX_CHANGE_COOKIE,
203 AT_STATX_SYNC_AS_STAT) ||
204 !(stat.result_mask & STATX_CHANGE_COOKIE) ||
205 stat.change_cookie != iint->real_inode.version) {
206 iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
207 iint->measured_pcrs = 0;
208 if (update)
209 ima_update_xattr(iint, file);
210 }
211 }
212 mutex_unlock(&iint->mutex);
213 }
214
215 /**
216 * ima_file_free - called on __fput()
217 * @file: pointer to file structure being freed
218 *
219 * Flag files that changed, based on i_version
220 */
ima_file_free(struct file * file)221 static void ima_file_free(struct file *file)
222 {
223 struct inode *inode = file_inode(file);
224 struct ima_iint_cache *iint;
225
226 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
227 return;
228
229 iint = ima_iint_find(inode);
230 if (!iint)
231 return;
232
233 ima_check_last_writer(iint, inode, file);
234 }
235
process_measurement(struct file * file,const struct cred * cred,struct lsm_prop * prop,char * buf,loff_t size,int mask,enum ima_hooks func,enum kernel_read_file_id read_id,bool bprm_is_check)236 static int process_measurement(struct file *file, const struct cred *cred,
237 struct lsm_prop *prop, char *buf, loff_t size,
238 int mask, enum ima_hooks func,
239 enum kernel_read_file_id read_id,
240 bool bprm_is_check)
241 {
242 struct inode *real_inode, *inode = file_inode(file);
243 struct ima_iint_cache *iint = NULL;
244 struct ima_template_desc *template_desc = NULL;
245 struct inode *metadata_inode;
246 char *pathbuf = NULL;
247 char filename[NAME_MAX];
248 const char *pathname = NULL;
249 int rc = 0, action, must_appraise = 0;
250 int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
251 struct evm_ima_xattr_data *xattr_value = NULL;
252 struct modsig *modsig = NULL;
253 int xattr_len = 0;
254 bool violation_check;
255 enum hash_algo hash_algo;
256 unsigned int allowed_algos = 0;
257
258 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
259 return 0;
260
261 /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
262 * bitmask based on the appraise/audit/measurement policy.
263 * Included is the appraise submask.
264 */
265 action = ima_get_action(file_mnt_idmap(file), inode, cred, prop,
266 mask, func, &pcr, &template_desc, NULL,
267 &allowed_algos);
268 violation_check = ((func == FILE_CHECK || func == MMAP_CHECK ||
269 func == MMAP_CHECK_REQPROT) &&
270 (ima_policy_flag & IMA_MEASURE) &&
271 ((action & IMA_MEASURE) ||
272 (file->f_mode & FMODE_WRITE)));
273 if (!action && !violation_check)
274 return 0;
275
276 must_appraise = action & IMA_APPRAISE;
277
278 /* Is the appraise rule hook specific? */
279 if (action & IMA_FILE_APPRAISE)
280 func = FILE_CHECK;
281
282 inode_lock(inode);
283
284 if (action) {
285 iint = ima_inode_get(inode);
286 if (!iint)
287 rc = -ENOMEM;
288 }
289
290 if (!rc && violation_check)
291 ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
292 &pathbuf, &pathname, filename);
293
294 inode_unlock(inode);
295
296 if (rc)
297 goto out;
298 if (!action)
299 goto out;
300
301 mutex_lock(&iint->mutex);
302
303 if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
304 /*
305 * Reset appraisal flags (action and non-action rule-specific)
306 * if ima_inode_post_setattr was called.
307 */
308 iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
309 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
310 IMA_NONACTION_RULE_FLAGS);
311
312 /*
313 * Re-evaulate the file if either the xattr has changed or the
314 * kernel has no way of detecting file change on the filesystem.
315 * (Limited to privileged mounted filesystems.)
316 */
317 if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) ||
318 ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
319 !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) &&
320 !(action & IMA_FAIL_UNVERIFIABLE_SIGS))) {
321 iint->flags &= ~IMA_DONE_MASK;
322 iint->measured_pcrs = 0;
323 }
324
325 /*
326 * On stacked filesystems, detect and re-evaluate file data and
327 * metadata changes.
328 */
329 real_inode = d_real_inode(file_dentry(file));
330 if (real_inode != inode &&
331 (action & IMA_DO_MASK) && (iint->flags & IMA_DONE_MASK)) {
332 if (!IS_I_VERSION(real_inode) ||
333 integrity_inode_attrs_changed(&iint->real_inode,
334 real_inode)) {
335 iint->flags &= ~IMA_DONE_MASK;
336 iint->measured_pcrs = 0;
337 }
338
339 /*
340 * Reset the EVM status when metadata changed.
341 */
342 metadata_inode = d_inode(d_real(file_dentry(file),
343 D_REAL_METADATA));
344 if (evm_metadata_changed(inode, metadata_inode))
345 iint->flags &= ~(IMA_APPRAISED |
346 IMA_APPRAISED_SUBMASK);
347 }
348
349 /* Determine if already appraised/measured based on bitmask
350 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
351 * IMA_AUDIT, IMA_AUDITED)
352 */
353 iint->flags |= action;
354 action &= IMA_DO_MASK;
355 action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
356
357 /* If target pcr is already measured, unset IMA_MEASURE action */
358 if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
359 action ^= IMA_MEASURE;
360
361 /* HASH sets the digital signature and update flags, nothing else */
362 if ((action & IMA_HASH) &&
363 !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
364 xattr_len = ima_read_xattr(file_dentry(file),
365 &xattr_value, xattr_len);
366 if ((xattr_value && xattr_len > 2) &&
367 (xattr_value->type == EVM_IMA_XATTR_DIGSIG))
368 set_bit(IMA_DIGSIG, &iint->atomic_flags);
369 iint->flags |= IMA_HASHED;
370 action ^= IMA_HASH;
371 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
372 }
373
374 /* Nothing to do, just return existing appraised status */
375 if (!action) {
376 if (must_appraise) {
377 rc = mmap_violation_check(func, file, &pathbuf,
378 &pathname, filename);
379 if (!rc)
380 rc = ima_get_cache_status(iint, func);
381 }
382 goto out_locked;
383 }
384
385 if ((action & IMA_APPRAISE_SUBMASK) ||
386 strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
387 /* read 'security.ima' */
388 xattr_len = ima_read_xattr(file_dentry(file),
389 &xattr_value, xattr_len);
390
391 /*
392 * Read the appended modsig if allowed by the policy, and allow
393 * an additional measurement list entry, if needed, based on the
394 * template format and whether the file was already measured.
395 */
396 if (iint->flags & IMA_MODSIG_ALLOWED) {
397 rc = ima_read_modsig(func, buf, size, &modsig);
398
399 if (!rc && ima_template_has_modsig(template_desc) &&
400 iint->flags & IMA_MEASURED)
401 action |= IMA_MEASURE;
402 }
403 }
404
405 hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
406
407 rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
408 if (rc != 0 && rc != -EBADF && rc != -EINVAL)
409 goto out_locked;
410
411 /* Defer measuring/appraising kernel modules to READING_MODULE */
412 if (read_id == READING_MODULE_COMPRESSED) {
413 must_appraise = 0;
414 goto out_locked;
415 }
416
417 if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */
418 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
419
420 if (action & IMA_MEASURE)
421 ima_store_measurement(iint, file, pathname,
422 xattr_value, xattr_len, modsig, pcr,
423 template_desc);
424 if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
425 rc = ima_check_blacklist(iint, modsig, pcr);
426 if (rc != -EPERM) {
427 inode_lock(inode);
428 rc = ima_appraise_measurement(func, iint, file,
429 pathname, xattr_value,
430 xattr_len, modsig,
431 bprm_is_check);
432 inode_unlock(inode);
433 }
434 if (!rc)
435 rc = mmap_violation_check(func, file, &pathbuf,
436 &pathname, filename);
437 }
438 if (action & IMA_AUDIT)
439 ima_audit_measurement(iint, pathname);
440
441 if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
442 rc = 0;
443
444 /* Ensure the digest was generated using an allowed algorithm */
445 if (rc == 0 && must_appraise && allowed_algos != 0 &&
446 (allowed_algos & (1U << hash_algo)) == 0) {
447 rc = -EACCES;
448
449 integrity_audit_msg(AUDIT_INTEGRITY_DATA, file_inode(file),
450 pathname, "collect_data",
451 "denied-hash-algorithm", rc, 0);
452 }
453 out_locked:
454 if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
455 !(iint->flags & IMA_NEW_FILE))
456 rc = -EACCES;
457 mutex_unlock(&iint->mutex);
458 kfree(xattr_value);
459 ima_free_modsig(modsig);
460 out:
461 if (pathbuf)
462 __putname(pathbuf);
463 if (must_appraise) {
464 if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
465 return -EACCES;
466 if (file->f_mode & FMODE_WRITE)
467 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
468 }
469 return 0;
470 }
471
472 /**
473 * ima_file_mmap - based on policy, collect/store measurement.
474 * @file: pointer to the file to be measured (May be NULL)
475 * @reqprot: protection requested by the application
476 * @prot: protection that will be applied by the kernel
477 * @flags: operational flags
478 *
479 * Measure files being mmapped executable based on the ima_must_measure()
480 * policy decision.
481 *
482 * On success return 0. On integrity appraisal error, assuming the file
483 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
484 */
ima_file_mmap(struct file * file,unsigned long reqprot,unsigned long prot,unsigned long flags)485 static int ima_file_mmap(struct file *file, unsigned long reqprot,
486 unsigned long prot, unsigned long flags)
487 {
488 struct lsm_prop prop;
489 int ret;
490
491 if (!file)
492 return 0;
493
494 security_current_getlsmprop_subj(&prop);
495
496 if (reqprot & PROT_EXEC) {
497 ret = process_measurement(file, current_cred(), &prop, NULL,
498 0, MAY_EXEC, MMAP_CHECK_REQPROT, 0,
499 false);
500 if (ret)
501 return ret;
502 }
503
504 if (prot & PROT_EXEC)
505 return process_measurement(file, current_cred(), &prop, NULL,
506 0, MAY_EXEC, MMAP_CHECK, 0, false);
507
508 return 0;
509 }
510
511 /**
512 * ima_file_mprotect - based on policy, limit mprotect change
513 * @vma: vm_area_struct protection is set to
514 * @reqprot: protection requested by the application
515 * @prot: protection that will be applied by the kernel
516 *
517 * Files can be mmap'ed read/write and later changed to execute to circumvent
518 * IMA's mmap appraisal policy rules. Due to locking issues (mmap semaphore
519 * would be taken before i_mutex), files can not be measured or appraised at
520 * this point. Eliminate this integrity gap by denying the mprotect
521 * PROT_EXECUTE change, if an mmap appraise policy rule exists.
522 *
523 * On mprotect change success, return 0. On failure, return -EACESS.
524 */
ima_file_mprotect(struct vm_area_struct * vma,unsigned long reqprot,unsigned long prot)525 static int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
526 unsigned long prot)
527 {
528 struct ima_template_desc *template = NULL;
529 struct file *file;
530 char filename[NAME_MAX];
531 char *pathbuf = NULL;
532 const char *pathname = NULL;
533 struct inode *inode;
534 struct lsm_prop prop;
535 int result = 0;
536 int action;
537 int pcr;
538
539 /* Is mprotect making an mmap'ed file executable? */
540 if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
541 !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
542 return 0;
543
544 security_current_getlsmprop_subj(&prop);
545 inode = file_inode(vma->vm_file);
546 action = ima_get_action(file_mnt_idmap(vma->vm_file), inode,
547 current_cred(), &prop, MAY_EXEC, MMAP_CHECK,
548 &pcr, &template, NULL, NULL);
549 action |= ima_get_action(file_mnt_idmap(vma->vm_file), inode,
550 current_cred(), &prop, MAY_EXEC,
551 MMAP_CHECK_REQPROT, &pcr, &template, NULL,
552 NULL);
553
554 /* Is the mmap'ed file in policy? */
555 if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
556 return 0;
557
558 if (action & IMA_APPRAISE_SUBMASK)
559 result = -EPERM;
560
561 file = vma->vm_file;
562 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
563 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname,
564 "collect_data", "failed-mprotect", result, 0);
565 if (pathbuf)
566 __putname(pathbuf);
567
568 return result;
569 }
570
571 /**
572 * ima_bprm_check - based on policy, collect/store measurement.
573 * @bprm: contains the linux_binprm structure
574 *
575 * The OS protects against an executable file, already open for write,
576 * from being executed in deny_write_access() and an executable file,
577 * already open for execute, from being modified in get_write_access().
578 * So we can be certain that what we verify and measure here is actually
579 * what is being executed.
580 *
581 * On success return 0. On integrity appraisal error, assuming the file
582 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
583 */
ima_bprm_check(struct linux_binprm * bprm)584 static int ima_bprm_check(struct linux_binprm *bprm)
585 {
586 struct lsm_prop prop;
587
588 security_current_getlsmprop_subj(&prop);
589 return process_measurement(bprm->file, current_cred(),
590 &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0,
591 bprm->is_check);
592 }
593
594 /**
595 * ima_creds_check - based on policy, collect/store measurement.
596 * @bprm: contains the linux_binprm structure
597 * @file: contains the file descriptor of the binary being executed
598 *
599 * The OS protects against an executable file, already open for write,
600 * from being executed in deny_write_access() and an executable file,
601 * already open for execute, from being modified in get_write_access().
602 * So we can be certain that what we verify and measure here is actually
603 * what is being executed.
604 *
605 * The difference from ima_bprm_check() is that ima_creds_check() is invoked
606 * only after determining the final binary to be executed without interpreter,
607 * and not when searching for intermediate binaries. The reason is that since
608 * commit 56305aa9b6fab ("exec: Compute file based creds only once"), the
609 * credentials to be applied to the process are calculated only at that stage
610 * (bprm_creds_from_file security hook instead of bprm_check_security).
611 *
612 * On success return 0. On integrity appraisal error, assuming the file
613 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
614 */
ima_creds_check(struct linux_binprm * bprm,const struct file * file)615 static int ima_creds_check(struct linux_binprm *bprm, const struct file *file)
616 {
617 struct lsm_prop prop;
618
619 security_current_getlsmprop_subj(&prop);
620 return process_measurement((struct file *)file, bprm->cred, &prop, NULL,
621 0, MAY_EXEC, CREDS_CHECK, 0, false);
622 }
623
624 /**
625 * ima_bprm_creds_for_exec - collect/store/appraise measurement.
626 * @bprm: contains the linux_binprm structure
627 *
628 * Based on the IMA policy and the execveat(2) AT_EXECVE_CHECK flag, measure
629 * and appraise the integrity of a file to be executed by script interpreters.
630 * Unlike any of the other LSM hooks where the kernel enforces file integrity,
631 * enforcing file integrity is left up to the discretion of the script
632 * interpreter (userspace).
633 *
634 * On success return 0. On integrity appraisal error, assuming the file
635 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
636 */
ima_bprm_creds_for_exec(struct linux_binprm * bprm)637 static int ima_bprm_creds_for_exec(struct linux_binprm *bprm)
638 {
639 /*
640 * As security_bprm_check() is called multiple times, both
641 * the script and the shebang interpreter are measured, appraised,
642 * and audited. Limit usage of this LSM hook to just measuring,
643 * appraising, and auditing the indirect script execution
644 * (e.g. ./sh example.sh).
645 */
646 if (!bprm->is_check)
647 return 0;
648
649 return ima_bprm_check(bprm);
650 }
651
652 /**
653 * ima_file_check - based on policy, collect/store measurement.
654 * @file: pointer to the file to be measured
655 * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
656 *
657 * Measure files based on the ima_must_measure() policy decision.
658 *
659 * On success return 0. On integrity appraisal error, assuming the file
660 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
661 */
ima_file_check(struct file * file,int mask)662 static int ima_file_check(struct file *file, int mask)
663 {
664 struct lsm_prop prop;
665
666 security_current_getlsmprop_subj(&prop);
667 return process_measurement(file, current_cred(), &prop, NULL, 0,
668 mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
669 MAY_APPEND), FILE_CHECK, 0, false);
670 }
671
__ima_inode_hash(struct inode * inode,struct file * file,char * buf,size_t buf_size)672 static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,
673 size_t buf_size)
674 {
675 struct ima_iint_cache *iint = NULL, tmp_iint;
676 int rc, hash_algo;
677
678 if (ima_policy_flag) {
679 iint = ima_iint_find(inode);
680 if (iint)
681 mutex_lock(&iint->mutex);
682 }
683
684 if ((!iint || !(iint->flags & IMA_COLLECTED)) && file) {
685 if (iint)
686 mutex_unlock(&iint->mutex);
687
688 memset(&tmp_iint, 0, sizeof(tmp_iint));
689 mutex_init(&tmp_iint.mutex);
690
691 rc = ima_collect_measurement(&tmp_iint, file, NULL, 0,
692 ima_hash_algo, NULL);
693 if (rc < 0) {
694 /* ima_hash could be allocated in case of failure. */
695 if (rc != -ENOMEM)
696 kfree(tmp_iint.ima_hash);
697
698 return -EOPNOTSUPP;
699 }
700
701 iint = &tmp_iint;
702 mutex_lock(&iint->mutex);
703 }
704
705 if (!iint)
706 return -EOPNOTSUPP;
707
708 /*
709 * ima_file_hash can be called when ima_collect_measurement has still
710 * not been called, we might not always have a hash.
711 */
712 if (!iint->ima_hash || !(iint->flags & IMA_COLLECTED)) {
713 mutex_unlock(&iint->mutex);
714 return -EOPNOTSUPP;
715 }
716
717 if (buf) {
718 size_t copied_size;
719
720 copied_size = min_t(size_t, iint->ima_hash->length, buf_size);
721 memcpy(buf, iint->ima_hash->digest, copied_size);
722 }
723 hash_algo = iint->ima_hash->algo;
724 mutex_unlock(&iint->mutex);
725
726 if (iint == &tmp_iint)
727 kfree(iint->ima_hash);
728
729 return hash_algo;
730 }
731
732 /**
733 * ima_file_hash - return a measurement of the file
734 * @file: pointer to the file
735 * @buf: buffer in which to store the hash
736 * @buf_size: length of the buffer
737 *
738 * On success, return the hash algorithm (as defined in the enum hash_algo).
739 * If buf is not NULL, this function also outputs the hash into buf.
740 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
741 * It generally just makes sense to pass a buffer capable of holding the largest
742 * possible hash: IMA_MAX_DIGEST_SIZE.
743 * The file hash returned is based on the entire file, including the appended
744 * signature.
745 *
746 * If the measurement cannot be performed, return -EOPNOTSUPP.
747 * If the parameters are incorrect, return -EINVAL.
748 */
ima_file_hash(struct file * file,char * buf,size_t buf_size)749 int ima_file_hash(struct file *file, char *buf, size_t buf_size)
750 {
751 if (!file)
752 return -EINVAL;
753
754 return __ima_inode_hash(file_inode(file), file, buf, buf_size);
755 }
756 EXPORT_SYMBOL_GPL(ima_file_hash);
757
758 /**
759 * ima_inode_hash - return the stored measurement if the inode has been hashed
760 * and is in the iint cache.
761 * @inode: pointer to the inode
762 * @buf: buffer in which to store the hash
763 * @buf_size: length of the buffer
764 *
765 * On success, return the hash algorithm (as defined in the enum hash_algo).
766 * If buf is not NULL, this function also outputs the hash into buf.
767 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
768 * It generally just makes sense to pass a buffer capable of holding the largest
769 * possible hash: IMA_MAX_DIGEST_SIZE.
770 * The hash returned is based on the entire contents, including the appended
771 * signature.
772 *
773 * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP.
774 * If the parameters are incorrect, return -EINVAL.
775 */
ima_inode_hash(struct inode * inode,char * buf,size_t buf_size)776 int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
777 {
778 if (!inode)
779 return -EINVAL;
780
781 return __ima_inode_hash(inode, NULL, buf, buf_size);
782 }
783 EXPORT_SYMBOL_GPL(ima_inode_hash);
784
785 /**
786 * ima_post_create_tmpfile - mark newly created tmpfile as new
787 * @idmap: idmap of the mount the inode was found from
788 * @inode: inode of the newly created tmpfile
789 *
790 * No measuring, appraising or auditing of newly created tmpfiles is needed.
791 * Skip calling process_measurement(), but indicate which newly, created
792 * tmpfiles are in policy.
793 */
ima_post_create_tmpfile(struct mnt_idmap * idmap,struct inode * inode)794 static void ima_post_create_tmpfile(struct mnt_idmap *idmap,
795 struct inode *inode)
796
797 {
798 struct ima_iint_cache *iint;
799 int must_appraise;
800
801 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
802 return;
803
804 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS,
805 FILE_CHECK);
806 if (!must_appraise)
807 return;
808
809 /* Nothing to do if we can't allocate memory */
810 iint = ima_inode_get(inode);
811 if (!iint)
812 return;
813
814 /* needed for writing the security xattrs */
815 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
816 iint->ima_file_status = INTEGRITY_PASS;
817 }
818
819 /**
820 * ima_post_path_mknod - mark as a new inode
821 * @idmap: idmap of the mount the inode was found from
822 * @dentry: newly created dentry
823 *
824 * Mark files created via the mknodat syscall as new, so that the
825 * file data can be written later.
826 */
ima_post_path_mknod(struct mnt_idmap * idmap,struct dentry * dentry)827 static void ima_post_path_mknod(struct mnt_idmap *idmap, struct dentry *dentry)
828 {
829 struct ima_iint_cache *iint;
830 struct inode *inode = dentry->d_inode;
831 int must_appraise;
832
833 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
834 return;
835
836 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS,
837 FILE_CHECK);
838 if (!must_appraise)
839 return;
840
841 /* Nothing to do if we can't allocate memory */
842 iint = ima_inode_get(inode);
843 if (!iint)
844 return;
845
846 /* needed for re-opening empty files */
847 iint->flags |= IMA_NEW_FILE;
848 }
849
850 /**
851 * ima_read_file - pre-measure/appraise hook decision based on policy
852 * @file: pointer to the file to be measured/appraised/audit
853 * @read_id: caller identifier
854 * @contents: whether a subsequent call will be made to ima_post_read_file()
855 *
856 * Permit reading a file based on policy. The policy rules are written
857 * in terms of the policy identifier. Appraising the integrity of
858 * a file requires a file descriptor.
859 *
860 * For permission return 0, otherwise return -EACCES.
861 */
ima_read_file(struct file * file,enum kernel_read_file_id read_id,bool contents)862 static int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
863 bool contents)
864 {
865 enum ima_hooks func;
866 struct lsm_prop prop;
867
868 /*
869 * Do devices using pre-allocated memory run the risk of the
870 * firmware being accessible to the device prior to the completion
871 * of IMA's signature verification any more than when using two
872 * buffers? It may be desirable to include the buffer address
873 * in this API and walk all the dma_map_single() mappings to check.
874 */
875
876 /*
877 * There will be a call made to ima_post_read_file() with
878 * a filled buffer, so we don't need to perform an extra
879 * read early here.
880 */
881 if (contents)
882 return 0;
883
884 /* Read entire file for all partial reads. */
885 func = read_idmap[read_id] ?: FILE_CHECK;
886 security_current_getlsmprop_subj(&prop);
887 return process_measurement(file, current_cred(), &prop, NULL, 0,
888 MAY_READ, func, 0, false);
889 }
890
891 const int read_idmap[READING_MAX_ID] = {
892 [READING_FIRMWARE] = FIRMWARE_CHECK,
893 [READING_MODULE] = MODULE_CHECK,
894 [READING_MODULE_COMPRESSED] = MODULE_CHECK,
895 [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
896 [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
897 [READING_POLICY] = POLICY_CHECK
898 };
899
900 /**
901 * ima_post_read_file - in memory collect/appraise/audit measurement
902 * @file: pointer to the file to be measured/appraised/audit
903 * @buf: pointer to in memory file contents
904 * @size: size of in memory file contents
905 * @read_id: caller identifier
906 *
907 * Measure/appraise/audit in memory file based on policy. Policy rules
908 * are written in terms of a policy identifier.
909 *
910 * On success return 0. On integrity appraisal error, assuming the file
911 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
912 */
ima_post_read_file(struct file * file,char * buf,loff_t size,enum kernel_read_file_id read_id)913 static int ima_post_read_file(struct file *file, char *buf, loff_t size,
914 enum kernel_read_file_id read_id)
915 {
916 enum ima_hooks func;
917 struct lsm_prop prop;
918
919 /* permit signed certs */
920 if (!file && read_id == READING_X509_CERTIFICATE)
921 return 0;
922
923 if (!file || !buf || size == 0) { /* should never happen */
924 if (ima_appraise & IMA_APPRAISE_ENFORCE)
925 return -EACCES;
926 return 0;
927 }
928
929 func = read_idmap[read_id] ?: FILE_CHECK;
930 security_current_getlsmprop_subj(&prop);
931 return process_measurement(file, current_cred(), &prop, buf, size,
932 MAY_READ, func, read_id, false);
933 }
934
935 /**
936 * ima_load_data - appraise decision based on policy
937 * @id: kernel load data caller identifier
938 * @contents: whether the full contents will be available in a later
939 * call to ima_post_load_data().
940 *
941 * Callers of this LSM hook can not measure, appraise, or audit the
942 * data provided by userspace. Enforce policy rules requiring a file
943 * signature (eg. kexec'ed kernel image).
944 *
945 * For permission return 0, otherwise return -EACCES.
946 */
ima_load_data(enum kernel_load_data_id id,bool contents)947 static int ima_load_data(enum kernel_load_data_id id, bool contents)
948 {
949 bool ima_enforce, sig_enforce;
950
951 ima_enforce =
952 (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
953
954 switch (id) {
955 case LOADING_KEXEC_IMAGE:
956 if (IS_ENABLED(CONFIG_KEXEC_SIG)
957 && arch_ima_get_secureboot()) {
958 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
959 return -EACCES;
960 }
961
962 if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) {
963 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
964 return -EACCES; /* INTEGRITY_UNKNOWN */
965 }
966 break;
967 case LOADING_FIRMWARE:
968 if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {
969 pr_err("Prevent firmware sysfs fallback loading.\n");
970 return -EACCES; /* INTEGRITY_UNKNOWN */
971 }
972 break;
973 case LOADING_MODULE:
974 sig_enforce = is_module_sig_enforced();
975
976 if (ima_enforce && (!sig_enforce
977 && (ima_appraise & IMA_APPRAISE_MODULES))) {
978 pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
979 return -EACCES; /* INTEGRITY_UNKNOWN */
980 }
981 break;
982 default:
983 break;
984 }
985 return 0;
986 }
987
988 /**
989 * ima_post_load_data - appraise decision based on policy
990 * @buf: pointer to in memory file contents
991 * @size: size of in memory file contents
992 * @load_id: kernel load data caller identifier
993 * @description: @load_id-specific description of contents
994 *
995 * Measure/appraise/audit in memory buffer based on policy. Policy rules
996 * are written in terms of a policy identifier.
997 *
998 * On success return 0. On integrity appraisal error, assuming the file
999 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
1000 */
ima_post_load_data(char * buf,loff_t size,enum kernel_load_data_id load_id,char * description)1001 static int ima_post_load_data(char *buf, loff_t size,
1002 enum kernel_load_data_id load_id,
1003 char *description)
1004 {
1005 if (load_id == LOADING_FIRMWARE) {
1006 if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
1007 (ima_appraise & IMA_APPRAISE_ENFORCE)) {
1008 pr_err("Prevent firmware loading_store.\n");
1009 return -EACCES; /* INTEGRITY_UNKNOWN */
1010 }
1011 return 0;
1012 }
1013
1014 /*
1015 * Measure the init_module syscall buffer containing the ELF image.
1016 */
1017 if (load_id == LOADING_MODULE)
1018 ima_measure_critical_data("modules", "init_module",
1019 buf, size, true, NULL, 0);
1020
1021 return 0;
1022 }
1023
1024 /**
1025 * process_buffer_measurement - Measure the buffer or the buffer data hash
1026 * @idmap: idmap of the mount the inode was found from
1027 * @inode: inode associated with the object being measured (NULL for KEY_CHECK)
1028 * @buf: pointer to the buffer that needs to be added to the log.
1029 * @size: size of buffer(in bytes).
1030 * @eventname: event name to be used for the buffer entry.
1031 * @func: IMA hook
1032 * @pcr: pcr to extend the measurement
1033 * @func_data: func specific data, may be NULL
1034 * @buf_hash: measure buffer data hash
1035 * @digest: buffer digest will be written to
1036 * @digest_len: buffer length
1037 *
1038 * Based on policy, either the buffer data or buffer data hash is measured
1039 *
1040 * Return: 0 if the buffer has been successfully measured, 1 if the digest
1041 * has been written to the passed location but not added to a measurement entry,
1042 * a negative value otherwise.
1043 */
process_buffer_measurement(struct mnt_idmap * idmap,struct inode * inode,const void * buf,int size,const char * eventname,enum ima_hooks func,int pcr,const char * func_data,bool buf_hash,u8 * digest,size_t digest_len)1044 int process_buffer_measurement(struct mnt_idmap *idmap,
1045 struct inode *inode, const void *buf, int size,
1046 const char *eventname, enum ima_hooks func,
1047 int pcr, const char *func_data,
1048 bool buf_hash, u8 *digest, size_t digest_len)
1049 {
1050 int ret = 0;
1051 const char *audit_cause = "ENOMEM";
1052 struct ima_template_entry *entry = NULL;
1053 struct ima_iint_cache iint = {};
1054 struct ima_event_data event_data = {.iint = &iint,
1055 .filename = eventname,
1056 .buf = buf,
1057 .buf_len = size};
1058 struct ima_template_desc *template;
1059 struct ima_max_digest_data hash;
1060 struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
1061 struct ima_digest_data, hdr);
1062 char digest_hash[IMA_MAX_DIGEST_SIZE];
1063 int digest_hash_len = hash_digest_size[ima_hash_algo];
1064 int violation = 0;
1065 int action = 0;
1066 struct lsm_prop prop;
1067
1068 if (digest && digest_len < digest_hash_len)
1069 return -EINVAL;
1070
1071 if (!ima_policy_flag && !digest)
1072 return -ENOENT;
1073
1074 template = ima_template_desc_buf();
1075 if (!template) {
1076 ret = -EINVAL;
1077 audit_cause = "ima_template_desc_buf";
1078 goto out;
1079 }
1080
1081 /*
1082 * Both LSM hooks and auxiliary based buffer measurements are
1083 * based on policy. To avoid code duplication, differentiate
1084 * between the LSM hooks and auxiliary buffer measurements,
1085 * retrieving the policy rule information only for the LSM hook
1086 * buffer measurements.
1087 */
1088 if (func) {
1089 security_current_getlsmprop_subj(&prop);
1090 action = ima_get_action(idmap, inode, current_cred(),
1091 &prop, 0, func, &pcr, &template,
1092 func_data, NULL);
1093 if (!(action & IMA_MEASURE) && !digest)
1094 return -ENOENT;
1095 }
1096
1097 if (!pcr)
1098 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
1099
1100 iint.ima_hash = hash_hdr;
1101 iint.ima_hash->algo = ima_hash_algo;
1102 iint.ima_hash->length = hash_digest_size[ima_hash_algo];
1103
1104 ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
1105 if (ret < 0) {
1106 audit_cause = "hashing_error";
1107 goto out;
1108 }
1109
1110 if (buf_hash) {
1111 memcpy(digest_hash, hash_hdr->digest, digest_hash_len);
1112
1113 ret = ima_calc_buffer_hash(digest_hash, digest_hash_len,
1114 iint.ima_hash);
1115 if (ret < 0) {
1116 audit_cause = "hashing_error";
1117 goto out;
1118 }
1119
1120 event_data.buf = digest_hash;
1121 event_data.buf_len = digest_hash_len;
1122 }
1123
1124 if (digest)
1125 memcpy(digest, iint.ima_hash->digest, digest_hash_len);
1126
1127 if (!ima_policy_flag || (func && !(action & IMA_MEASURE)))
1128 return 1;
1129
1130 ret = ima_alloc_init_template(&event_data, &entry, template);
1131 if (ret < 0) {
1132 audit_cause = "alloc_entry";
1133 goto out;
1134 }
1135
1136 ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr);
1137 if (ret < 0) {
1138 audit_cause = "store_entry";
1139 ima_free_template_entry(entry);
1140 }
1141
1142 out:
1143 if (ret < 0)
1144 integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname,
1145 func_measure_str(func),
1146 audit_cause, ret, 0, ret);
1147
1148 return ret;
1149 }
1150
1151 /**
1152 * ima_kexec_cmdline - measure kexec cmdline boot args
1153 * @kernel_fd: file descriptor of the kexec kernel being loaded
1154 * @buf: pointer to buffer
1155 * @size: size of buffer
1156 *
1157 * Buffers can only be measured, not appraised.
1158 */
ima_kexec_cmdline(int kernel_fd,const void * buf,int size)1159 void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
1160 {
1161 if (!buf || !size)
1162 return;
1163
1164 CLASS(fd, f)(kernel_fd);
1165 if (fd_empty(f))
1166 return;
1167
1168 process_buffer_measurement(file_mnt_idmap(fd_file(f)), file_inode(fd_file(f)),
1169 buf, size, "kexec-cmdline", KEXEC_CMDLINE, 0,
1170 NULL, false, NULL, 0);
1171 }
1172
1173 /**
1174 * ima_measure_critical_data - measure kernel integrity critical data
1175 * @event_label: unique event label for grouping and limiting critical data
1176 * @event_name: event name for the record in the IMA measurement list
1177 * @buf: pointer to buffer data
1178 * @buf_len: length of buffer data (in bytes)
1179 * @hash: measure buffer data hash
1180 * @digest: buffer digest will be written to
1181 * @digest_len: buffer length
1182 *
1183 * Measure data critical to the integrity of the kernel into the IMA log
1184 * and extend the pcr. Examples of critical data could be various data
1185 * structures, policies, and states stored in kernel memory that can
1186 * impact the integrity of the system.
1187 *
1188 * Return: 0 if the buffer has been successfully measured, 1 if the digest
1189 * has been written to the passed location but not added to a measurement entry,
1190 * a negative value otherwise.
1191 */
ima_measure_critical_data(const char * event_label,const char * event_name,const void * buf,size_t buf_len,bool hash,u8 * digest,size_t digest_len)1192 int ima_measure_critical_data(const char *event_label,
1193 const char *event_name,
1194 const void *buf, size_t buf_len,
1195 bool hash, u8 *digest, size_t digest_len)
1196 {
1197 if (!event_name || !event_label || !buf || !buf_len)
1198 return -ENOPARAM;
1199
1200 return process_buffer_measurement(&nop_mnt_idmap, NULL, buf, buf_len,
1201 event_name, CRITICAL_DATA, 0,
1202 event_label, hash, digest,
1203 digest_len);
1204 }
1205 EXPORT_SYMBOL_GPL(ima_measure_critical_data);
1206
1207 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
1208
1209 /**
1210 * ima_kernel_module_request - Prevent crypto-pkcs1(rsa,*) requests
1211 * @kmod_name: kernel module name
1212 *
1213 * Avoid a verification loop where verifying the signature of the modprobe
1214 * binary requires executing modprobe itself. Since the modprobe iint->mutex
1215 * is already held when the signature verification is performed, a deadlock
1216 * occurs as soon as modprobe is executed within the critical region, since
1217 * the same lock cannot be taken again.
1218 *
1219 * This happens when public_key_verify_signature(), in case of RSA algorithm,
1220 * use alg_name to store internal information in order to construct an
1221 * algorithm on the fly, but crypto_larval_lookup() will try to use alg_name
1222 * in order to load a kernel module with same name.
1223 *
1224 * Since we don't have any real "crypto-pkcs1(rsa,*)" kernel modules,
1225 * we are safe to fail such module request from crypto_larval_lookup(), and
1226 * avoid the verification loop.
1227 *
1228 * Return: Zero if it is safe to load the kernel module, -EINVAL otherwise.
1229 */
ima_kernel_module_request(char * kmod_name)1230 static int ima_kernel_module_request(char *kmod_name)
1231 {
1232 if (strncmp(kmod_name, "crypto-pkcs1(rsa,", 17) == 0)
1233 return -EINVAL;
1234
1235 return 0;
1236 }
1237
1238 #endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
1239
init_ima(void)1240 static int __init init_ima(void)
1241 {
1242 int error;
1243
1244 /*Note that turning IMA off is intentionally limited to kdump kernel.*/
1245 if (ima_disabled && is_kdump_kernel()) {
1246 pr_info("IMA functionality is disabled");
1247 return 0;
1248 }
1249
1250 ima_appraise_parse_cmdline();
1251 ima_init_template_list();
1252 hash_setup(CONFIG_IMA_DEFAULT_HASH);
1253 error = ima_init();
1254
1255 if (error && strcmp(hash_algo_name[ima_hash_algo],
1256 CONFIG_IMA_DEFAULT_HASH) != 0) {
1257 pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
1258 hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
1259 hash_setup_done = 0;
1260 hash_setup(CONFIG_IMA_DEFAULT_HASH);
1261 error = ima_init();
1262 }
1263
1264 if (error)
1265 return error;
1266
1267 error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
1268 if (error)
1269 pr_warn("Couldn't register LSM notifier, error %d\n", error);
1270
1271 if (!error)
1272 ima_update_policy_flags();
1273
1274 return error;
1275 }
1276
1277 static struct security_hook_list ima_hooks[] __ro_after_init = {
1278 LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
1279 LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec),
1280 LSM_HOOK_INIT(bprm_creds_from_file, ima_creds_check),
1281 LSM_HOOK_INIT(file_post_open, ima_file_check),
1282 LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile),
1283 LSM_HOOK_INIT(file_release, ima_file_free),
1284 LSM_HOOK_INIT(mmap_file, ima_file_mmap),
1285 LSM_HOOK_INIT(file_mprotect, ima_file_mprotect),
1286 LSM_HOOK_INIT(kernel_load_data, ima_load_data),
1287 LSM_HOOK_INIT(kernel_post_load_data, ima_post_load_data),
1288 LSM_HOOK_INIT(kernel_read_file, ima_read_file),
1289 LSM_HOOK_INIT(kernel_post_read_file, ima_post_read_file),
1290 LSM_HOOK_INIT(path_post_mknod, ima_post_path_mknod),
1291 #ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS
1292 LSM_HOOK_INIT(key_post_create_or_update, ima_post_key_create_or_update),
1293 #endif
1294 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
1295 LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request),
1296 #endif
1297 LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu),
1298 };
1299
1300 static const struct lsm_id ima_lsmid = {
1301 .name = "ima",
1302 .id = LSM_ID_IMA,
1303 };
1304
init_ima_lsm(void)1305 static int __init init_ima_lsm(void)
1306 {
1307 ima_iintcache_init();
1308 security_add_hooks(ima_hooks, ARRAY_SIZE(ima_hooks), &ima_lsmid);
1309 init_ima_appraise_lsm(&ima_lsmid);
1310 return 0;
1311 }
1312
1313 struct lsm_blob_sizes ima_blob_sizes __ro_after_init = {
1314 .lbs_inode = sizeof(struct ima_iint_cache *),
1315 };
1316
1317 DEFINE_LSM(ima) = {
1318 .id = &ima_lsmid,
1319 .init = init_ima_lsm,
1320 .order = LSM_ORDER_LAST,
1321 .blobs = &ima_blob_sizes,
1322 /* Start IMA after the TPM is available */
1323 .initcall_late = init_ima,
1324 };
1325